Ossification in a long bone (40X)

Ossification in a long bone. Image copyright: Mathias Nordvi, CC BY-NC-ND 4.0. (Tissue stain: Azan).

This is a cross section of a long bone covered by periost and its central cavity is filled with bone marrow. The surrounding tissue displays a cross section of many common structures. The arteries appear circular and are filled with blood, while the veins have an irregular shape compared to the arteries. There is also a nerve displaying numerous fascicles.